1. Field of the Invention
The present invention relates to a spindle motor, a disk drive apparatus and a method for manufacturing the spindle motor.
2. Description of the Related Art
A hard disk drive apparatus or an optical disk drive apparatus is equipped with a spindle motor for rotating a disk about the center axis thereof. The spindle motor includes a housing, a stator unit fixed to the housing and a rotor unit arranged to rotate while supporting a disk. In the spindle motor, torque acting about the center axis is generated by the magnetic flux flowing between the stator unit and the rotor unit, whereby the rotor unit is rotated with respect to the stator unit.
A spindle motor including a stator assembly, a hub, a back iron and a magnet is disclosed in, e.g., U.S. Pat. No. 6,771,461. With the spindle motor disclosed in the '461 patent, only the upper portion of the inner circumferential surface of the back iron is fixed to the hub by an adhesive agent. However, the bonding area is small in this configuration, which makes it difficult to securely fix the back iron to the hub.